MAINTAINERS: add Alexandre Courbot as Rust reviewer

MAINTAINERS: add Alexandre Courbot as Rust reviewer

Alexandre has been involved with the Rust for Linux project for more
than a year now. He is one of the main contributors to Nova [1], the
Rust driver for NVIDIA GPUs, and has authored core Rust infrastructure
motivated by that work, such as the `num` module with the `Bounded`
integer type, the `register!` and `bitfield!` macros, as well as
improvements to abstractions like DMA.

He maintains the nova-core driver, as well as the `RUST [NUM]`, `RUST
[BITFIELD]` and `RUST [INTEROP]` entries. In addition, he has been very
active reviewing Rust code in the mailing list.

He also proposed and implemented the `int_lowest_highest_one` feature
in the Rust standard library [2], which we should eventually use in
the kernel.

His experience maintaining a major Rust GPU driver and the abstractions
it needs will be very useful to have around in the future. Thus add him
to the `RUST` entry as reviewer.

Link: https://rust-for-linux.com/nova-gpu-driver
Link: https://github.com/rust-lang/rust/issues/145203
Acked-by: Alexandre Courbot <acourbot@nvidia.com>
Acked-by: Gary Guo <gary@garyguo.net>
Link: https://patch.msgid.link/20260611055538.61425-3-ojeda@kernel.org
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>